In recent years, as the giga Internet has been commercialized and expanded, the existing network device providing a high-speed Internet service of 100 Mbps level is being changed to a network device providing the gigabit Internet service. Giga-class Internet of 100 Mbps or more is commercially available and is provided to customers in earnest.
When using an optical cable or an unshielded twisted pair cable (UTP) 4 pair cable, it is possible to provide a 1 Gbps-class Internet service. However, it is difficult for a scheme using a UTP 2 pair cable or a telephone line to provide 1 Gbps-class Internet.
Unlike the optical cable, in a copper wire bundle cable environment, performance degradation occurs due to crosstalk in the same equipment or between equipments.
When a plurality of x digital subscriber line (xDSL) equipments shares a bundle cable, an influence on crosstalk increases and a performance degradation width increases.
Crosstalk occurs when the existing xDSL equipment and an equipment for providing the Giga Internet use the same frequency band. Particularly, due to characteristics of a copper wire bundle, inter-line crosstalk occurs, and as a result, when signals are transmitted to a plurality of lines, transmission performance deteriorates.
Thus, there is a need for a control and management technology for providing speeds suited to services subscribed to all subscribers in the presence of the crosstalk.